1. Field of the Invention
This invention relates to automatic clothes washing machines and the method of washing clothes and more particularly to an improved structure for increasing the unbalance capacity and the method of improving the inbalance capacity in a clothes washing machine.
2. Description of the Prior Art
Automatic clothes washing machines customarily provide a sequence of operations in order to wash, rinse, and extract water from the clothes contained in a basket. The sequence ordinarily includes a washing operation which, in a vertical axis type machine, is provided by an agitator movably arranged to oscillate back and forth within the basket; a first centrifugal liquid extraction operation in which the wash water is removed from the clothes by spinning the basket; a rinsing operation in which the clothes in the basket are rinsed in clean water while the agitator is oscillated; and a final centrifugal liquid extraction operation in which the basket is spun to remove the rinse water from the clothes. Machines having this type of cycle, or a variation thereof, generally produce highly satisfactory results in that the clothes in the machine come out properly cleaned and with a substantial part of the liquid removed.
A typical type clothes washing machine as shown and described in U.S. Pat. No. 3,570,274 assigned to the same assignee as the present invention. Such clothes washing machines have a stationary outer water containing tub and an inner perforated basket, the latter of which, during the centrifugal liquid extraction operations, is spun at high speed so that liquid is forced from the clothes within the basket through the perforations in the basket and into the outer tub. From the outer tub the liquid is removed from the machine to a drain by a conventional pumping means.
One disadvantage that can occur in such a clothes washing machine during the centrifugal liquid extraction operations is that should the articles being washed bunch up or have unequal weight distribution about the axis of rotation the basket may become unbalanced. If the unbalance is sufficient during acceleration of the spinning basket the basket may strike the outer tub which can result in injury to the machine and in some cases the striking may be so violent that the basket is prevented from reaching its intended rotational speed. The unbalance capacity of a given clothes washer machine is most noticeable when the clothes basket is being accelerated through its critical or resonance of vibration speed where it is likely to strike the tub due to an unbalance within the basket. It has been known that if the mass of the basket is increased such as for example by retaining a relatively high volume of water within the basket during its acceleration through the critical speed that the unbalance capacity will be improved. Accordingly unbalance problems most likely occur with small wash loads rather than large loads. For instance, such prior art disclosures are found in U.S. Pat. Nos. 3,306,082 and 2,976,998. The problem with these prior art clothes washing machines, however, is that while a greater volume of water may aid in improving the unbalance capacity of a machine, it detrimentally affects the power consumption necessary to accelerate the basket. In many cases the motor is insufficient to handle the load without increasing its size. In addition, the capability of extracting liquid from the clothes during the spinning is sacrificed.
By this invention we have improved the unbalance capacity of washing machines with no significant increase in power consumption and without significant decrease in liquid extraction from the clothes.